Abstract
Object identities appear stable despite noisy and constantly changing visual input, but it is unclear what mechanisms underlie such continuous perception. We have previously shown (Fischer & Whitney, 2014; Liberman et al., 2014) that observers experience serial dependence in the perception of orientation as well as face identity. This effect persists up to 15 seconds back in time and provides evidence for an object-selective continuity field. In the current study, we asked whether the continuity field promotes the perception of an object’s stable identity when it is temporarily occluded. While the subject fixated on a centered point, we presented an oriented Gabor patch that traveled from left to right; midway through its trajectory, it moved behind an occluder also centered on the screen. The Gabor could travel either in a straight and continuous trajectory (expected) or in a discontinuous trajectory (unexpected) behind the occluder. Both the Gabor disappearing behind the occluder (first Gabor) as well as the Gabor coming out (second Gabor) had randomly generated orientations. After the second Gabor was no longer on-screen, subjects adjusted a bar by rotating it to match the second Gabor’s orientation. Using this response, we tested whether the perceived orientation of the second Gabor was serially dependent on (i.e., captured by) the orientation of the first Gabor. We found that it was: the reported orientation of the second Gabor was pulled toward the orientation of the first Gabor. Importantly, this effect was significantly heightened when the Gabor followed the expected, continuous trajectory while it was occluded compared to the unexpected, discontinuous trajectory. This result suggests that sequential dependence in orientation perception takes advantage of expectations about a stable world, helping to maintain perceived object continuity despite interrupted visibility.
Meeting abstract presented at VSS 2015